I am trying to derive the Kepler equation:(adsbygoogle = window.adsbygoogle || []).push({});

M = E - e * sin(E)

where M=Mean Anomaly, e=Eccentricity and E=Eccentric Anomaly.

If you drop a perpendicular down from the object to the Perihelion-axis you can take:

a * cos(E) = a * e + Recl * cos (TA)

where Recl is the Ecliptic radius to the object from the Sun and TA=True Anomaly.

I am having a hard time equating M and TA because one is on the Ecliptic Plane and the other is on the Orbiting Plane.

Any hints are appreciated.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Derive the Kepler equation

**Physics Forums | Science Articles, Homework Help, Discussion**